sbrk_r.c

来自「FAT16 Filesystem on Philips LPC2000 seri」· C语言 代码 · 共 23 行

#include <reent.h>
#include <sysdefs.h>

extern char * end;
static char * heap = 0;

void * _sbrk_r (struct _reent *ptr, ptrdiff_t incr)
{
char * ret;
	if (heap == 0) heap = (char *) &end;
		// check to see if RAM is exhausted.
	if ((unsigned)(heap + incr) >= END_OF_THE_RAM_FIELD) {
		ret = (void *)-1;
	} else {
			// nope, RAM is still available to malloc()
			// note address and effectively reserve it.
		ret = heap; heap += incr;
	}
		// return address of newly allocated RAM.
	return (void *) ret;
}